Guys over at TC have it anywhere from 9:00 to 11:00. Fisher's illustrations show it at about 3:00 (right in line with the door lever). This holds true for all their models/illustrations. However, there is nothing in writting that I could find...

Fisher Body had Engineering specs for window crank "clocking", and they were referenced in the plant's O.D. (Operation Description) sheets; however, those O.D. sheets have never been published outside of GM. A complete Fisher Body O.D. sheet package is about four inches thick.